1. Field of the Invention
The invention relates to a radiation-sensitive resin composition and a compound.
2. Discussion of the Background
A semiconductor device (e.g., IC and LSI) production process utilizes microfabrication by means of lithography using a photoresist composition. Along with an increase in the degree of integration of integrated circuits, it has become necessary to form a sub-micron or quarter-micron fine pattern. Therefore, i-lines, KrF excimer laser light, or ArF excimer laser light having a short exposure wavelength has been used instead of g-lines. Lithography that utilizes electron beams, X-rays, or EUV light instead of excimer laser light has also been developed.
Lithography that utilizes EUV light is considered to be next-generation or third-generation patterning technology, and requires a positive-tone resist that exhibits high sensitivity and high resolution. In particular, it is very important to achieve an increase in sensitivity in order to reduce the wafer processing time. However, when increasing the sensitivity of a positive-tone resist used for EUV light, a deterioration in resolution and nano edge roughness occurs. Therefore, development of a resist that achieves high sensitivity, high resolution, and low nano edge roughness has been strongly desired. Note that the term “nano edge roughness” refers to a phenomenon in which the edge of the resist pattern irregularly changes with respect to the substrate in the direction perpendicular to the line direction due to the properties of the resist, so that a difference occurs between the design dimensions and the actual pattern dimensions when viewed from above. The difference from the design dimensions is transferred by etching using the resist as a mask, and causes a deterioration in electrical properties. As a result, a decrease in yield occurs. In particular, it is very important to reduce the nano edge roughness when forming a fine pattern having a line width of 32 nm or less using EUV light. High sensitivity, high resolution, an excellent pattern shape, and low nano edge roughness have a trade-off relationship. It is very important to achieve these properties at the same time.
KrF excimer laser resist technology has been mainly applied to an EUV positive-tone resist. For example, Japanese Patent Application Publication (KOKAI) No. 2001-166478 discloses a radiation-sensitive resin composition that includes a copolymer of 4-hydroxystyrene and 2-methyl-2-adamantyl acrylate. Japanese Patent Application Publication (KOKAI) No. 5-323590 discloses a radiation-sensitive resin composition that utilizes two types of photoacid generator. Japanese Patent Application Publication (KOKAI) No. 5-181279 discloses a radiation-sensitive resin composition that includes a photoacid generator that generates a strong acid and a photoacid generator that generates a weak acid. Japanese Patent Application Publication (KOKAI) No. 11-125907 discloses a radiation-sensitive resin composition that includes a compound that generates a carboxylic acid having a boiling point of 150° C. or more, and a compound that generates an acid other than a carboxylic acid.